1. Field of the Invention
The present invention relates to a power supply apparatus and, more particularly, to a power supply apparatus which is applied to an image forming apparatus such as copying apparatus, printer, or the like.
2. Related Background Art
Hitherto, in a voltage resonance type switching power supply apparatus which is generally used as such a kind of power supply apparatus, it is a point on designing that a resonance waveform on the primary side is stabilized and is certainly zero-cross switched.
In the above conventional power supply apparatus, however, when an L (impedance) load exists, a resonance frequency extremely changes due to its influence. Hitherto, there is a problem such that a control is not transiently stabilized or a response speed is slow in accordance with such an extreme change.